Conversion of synchronous type signals to start stop signals



Nov'. 27, 1945.

R. E MATHES CONVERSION 0F SYNCHRONOUS TYPE SIGNALS T0 START STOP SIGNALSOriginal Filed Nov. 26, 1942 Patented Nov. 27, 1945 CONVERSION FSYNCHRONOUS TYPE SIGNALS TO START STOP SIGNALS Richard E. Mathes, SilverSpring, Md., assignorV to Radio Corporation of America, a corporation ofDelaware Original application November 26, 1942, Serial No. 467,030.Divided and this application January 31, 1944, Serial No. 520,452

2 Claims.

This invention relates to electric telegraphs y employed to keep thereceiving distributor in synchronism and in phase with the transmittingdistributor.

In the other method, two additional code units, in effect, are added toeach code character, One is a start unit and the other a stop unit.

The rst method is generally employed in multiplexing by combiningseveral telegraph channels into one composite channel for transmissioneither by radio or by wire, though, of course, it is equally capable ofuse in single channel systems.

The second method is more generally used in single channel systems.

There are times when it is desirable to multiplex start-stop signalswith synchronous signals and also to use start-stop printers forprinting synchronous signals.

An object of the invention is to convert synchronous type signals intostart-stop signals by adding the starting and stoppingl units to eachcode character for operation of a start-stop printer, y

Another object is to convert synchronous signals into start-stop signalsby means of a local distributor.

Another object is to convert synchronous signals into start-stop signalsby means of a two ring distributor having two additional segments in onering.

Another object is to convert synchronous signals into start-stop signalsby means of a distributor having a segmented synchronous signal ring anda segmented adaptor ring with two additional segments therein.

Other objects will rappear in the following description, reference beinghad to the drawing, in which:

The single gure of the drawing is a diagrammatic illustration ofapparatus for converting synchronous type signals into start-stopsignals.

In the drawing a receiving circuit is shown for receiving synchronouslytransmitted signals of a three-channel system and converting the signalsof one channel into start-stop signals so that these may be printed on astart-stop printer, but, of course, similar apparatus could be used toconvert the signals of al1 three channels into start-stop signals, ifdesired.

In the drawing the composite signals sent out by a synchronousdistributor, such for example as shown in Fig, 1 of my said pendingapplication, come in over lines L1, L2, the latter being grounded, andthe multiplex distributor arm 62 carrying brush -63 separates thecomposite signals and sends each channel signal out over the threeindividual channel conductors, as is well known in the art. Thechannel64 is the only one that need be considered and it will be assumed toreceive the signals sent out by a startstop sender at the transmitter,though they could equally well be the signals from a synchronous typesender.

The distributor arm 62 will be rotated in synchronism with thetransmitter distributor by well-known means, generally indicated bymotor 55, and synchronized and phased in well-known ways (not shown).The ve start-stop code units assumed to be sent out by the transmitterwill be received in succession with no time separation between the endof one code character and the beginning of the next, as explained in mysaid application. Since these are to be used to operate a start-stopprinter, means is provided for inserting start-stop signals inappropriate places in the cycle. v

The ve synchronous code units will be sent into a locking circuit 65afor regeneration of the signals. Such a locking circuit is well known inthe art and is therefore indicated herein only in block diagram. Asuitable locking circuit is shown in detail in the patent to John W.Cox, No. 2,264,510, December 2, 1941, and the theory of operation isdescribed therein, It will be sufficient to say herein that theterminals of the locking circuit produce a potential drop acrossresistance 66 of one polarity for marks and another polarity for spacesand that the drop continpes until the locking circuit is thrown from oneposition to the other. The positive terminal of the supply voltage isconnected to the midpoint in this resistance, One terminal of resistance66 is connected to brush B1 contacting with slip ring 68 on adistributor generally indicated at 60. The other terminal of resistance`66 is connected through tlfe coil of relay 'l0 to brush ll engagingslip ring l2. Slip rings 68 and l2 are secured in any way to arm 13 ofthe distributor 69, which rotates at one-fifth the Speed of thedistributor arm V62. Distributor arm 13 carries brush 14, adapted toengage the ve equallyspaced contacts 15, 16, 11, 18 and 19, whenmultiplex distributor brush 63 is on contact 64. The ve contacts areshown virtually as segments of a circle, separated at the ends by stripsof insulation, but in practice thesesegments would be shortened soth-atthey would beI one-halfto one-fourth the angular length of the timesignal, as is usual in telegraph distributors- Contact is connected by aconductor 88 with contacts 11 and 19, while contact iis-connected byconductor 8| with contact 18. The upper end of resistance 66 isconnected through condenser 82 to conductor 89 and through condenser 83to conductor 8|.

Distributor 69 has seven arcuate contacts 84, 85, 86, 81, 88, 89 and 98,shown as having substantially equal length and separated by strips ofinsulation at adjoining ends, These contacts are preferably arranged tobe adjustable as a unit around the inner contacts 15 to 19, inclusive.This is` indicated conventionally by thev screw mechanism 98a. Thesecontacts preferably would beshortened in practice inthe same way ascontacts 15 to 19. Contact 8'4V constitutes the start Contact and lagscontact 15 in relation to the rotating arm 13, but overlaps suchcontact; This contact is connected to the minusterminal of the telegraphsupply battery 9|. Contact 85 is connected to the inner contact 15,contact 86 to the next. inner contact' 16, contact 81 to inner contactv11, contact 88 to inner contact 18', contact 89 to inner contact 19 andcontact 98 to the positive terminal of battery 9 I,

The relay 18 is polarized because it has been assumedithat the lockingcircuit 65a places alternate plus and minus potentials in resistance 66;Of course, on-and-oi potentials could have been produced in, thisresistanceby the locking circuit and inthat case the relay would benonpolarized and biased to one position. The tongue 92 of the polarizedrelay 18 in one position engages with the positive terminal'and in theother position with the other terminal that has no potential. Thestart-stop printer 93 has been assumed to work on on-and-oif current,but it could equally well operate on plus and minus current', in whichcase the blank terminal of relay 18 would be connected to a minuspotential. The tongue 92 of the relay is connected in the usual way toone terminal of' the start-stop printer 93, the other terminal of thisprinter being grounded to the plus and minus terminal of battery 9|.

The operation of the, receiving circuit may be described as follows:

The; incoming synchronous signals are separated' by the distributor arm62 in a Well-known way and produce plus or minus potential drops inresistance 66 and these potentials will be produced in synchronism withthe movement of the rotating distributor arm 13, When brush 14a ondistributor arm 13. engages outer contact 98, current will now frombattery, 9| through contact 98, `brush 14a, slip ring 12, brush 1| andthe coil ofrelay 18', back to the mid-terminal of the battery. Tris willthrow the relay tongue 92 against the positive contact, which willproduce a stop signal for the start-stop printer. 'I'he first code unitof a character will be received soon thereafter and will produce apotential in resistance 66 while the distributor brush 14 is on contact15. This will produce current ow through brush 61 relay ring 68, brush14, contact 15, conductor 88. and condenser 82 to the other terminal ofthe resistance. The polarity of the charge in condenser 82 will, ofcourse, depend upon the character of the signal being received. If it isa mark, the condenser will be charged with one polarity and if a space,an opposite polarity,

The brush 14a next engages. contact 84 and current flows from themidpoint terminal of battery 9| to the lower end of the coil of relay10, through brush 1|, ring 12 and brush 14a to the minus terminal of thebattery. This will energize relay 18 in an opposite direction and throwtongue 92 against the blank contact. This constitutes the start signal(no current) of the printer and the printer will start in a Way wellknown in the art, Before the printer has reached the rst code position,brush 14 of the distributor will have left contact 15 and engagedcontact 16. Atv this time signal potential still existed in resistance66, but it was cut off from the condenser when the brush 14 left contact15. This will produce charging current of either. one polarity or theother from the lower terminal of resistance 66 through brush 61, ring68, brush 14, contact`v 16, conductor 8| and condenser 83 to the otherterminal of resistance 66- The rst and second signals, of the codecharacter are now stored, in condensers 82 and 83 before` thedistributor brush 14av engages outer contact 85. When contact 85 isengaged by the brush 14a, condenser 82 willdischarge through conductorS9, contact 85, brush 14a, distributor ring 12, brush 1| and the coil ofrelay 18 back through conductor 94 tothe other terminal of thecondenser. The relay tongue 92 will then be positioned either againstthe positive contact or the blank contact, depending upon the polarityof the signals stored in this condenser. The tongue 82 stays in itsoperated position until moved to the opposite position, as well known inthe art. While brush 14a has reached the middle of contact 8,5, thestart-stop printer 93 will be in position for receiving the rst codeunit, and will operate the first selector bar in one. direction or theother.

When the distributor arm13, passes oi of inner contact 16, it willengage contact 11 and charge condenser 82 in a way already described,Slightly before this time brush 14a willA engage the outer contact 86and permit the discharging of the second code unit stored in condenser83 through theV coil of relay 10. This will pass through conductor 8|,contact 86, brush 14a, slip ring 12', brush 1|, the coil of relay 18 andconductor 94 to the other terminal or the battery. This will positionthe tongue 92 against either the positive contact or the blank contact,dependent upon the signal. The start-stop printer reaches the secondcode position when the brush 14a is in the middle of contact 86 andthesecond selector bar will be thus moved in response to either a mark or aspace signal.

When the distributor arm moves` the brush 14a onto outer contact 81,condenser 82 discharges throughl the coil of relay 18 and throws thetongue 92 onto thel positive contactA for a mark or onto the blankcontact for a space. This is the stored signal of the third code unitand will cause the printer 93 to move the third selector bar when thethird code position of` the printer is reached.

As the distributor arm 13 continues to rotate, brush 14. engages contact18 andthe incoming fourth signal is stored in condenser 83. Thedistributor arm 13 next brings brush 14a onto outer contact 88 and thefourthr signal unit just stored in condenser 83 discharges through thecoil of relay 'l0 in position to cause the selection of the fourthselector bar in printer 93.

The distributor arm 13 then brings brush 14 into engagement with innercontact 19 and stores the fifth signal code unit in condenser 82 andwhen brush 14a engages the fth contact 89, this condenser dischargesthrough the coil of relay 'l0 to produce the movement of the fthselector bar in the start-stop printer.

When the distributor brush 14a engages the outer contact 90, a stopsignal is produced in the start-stop printer 93, as already described.'I'he reception of one character and its printing has now beencompleted. The signal code units of the second character will be storedand cause the operation of the printer 93, in the way already described.

It usually will not be necessary to store the fourth and fth code unitsin the condenser, as the brush 14a will usually be on the outer contacts88 and 89 to permit the received signal current to pass directly throughthe coil of relay 10. However, it is preferable to connect all vecontacts to condensers 82 and 83 and to interconnect the inner contactswith the outer ones, as described, so that the printer will operateeither directly from the received signals or from such signals stored inthe condensers, and it is immaterial where one commences and the otherleaves 01T.

I have shown one embodiment for converting synchronous signals at thereceiver into startstop signals, but it will be apparent that variousmodifications may be used without departing from the spirit of theinvention.

Having described my invention, what I claim l. In apparatus forconverting to start-stop signals the synchronous code unit signalsrements to different potentials in the source of supply, a condenserhaving one terminal connected to alternate segments of the rst series, asecond condenser having one terminal connected to the remaining segmentsof the first series, a line relay having a coil with one terminalconnected to an intermediate potential in the source of supply, a signaloutput device connected to said single channel having one terminalconnected to the remaining terminals of said condensers, means forconnecting the other terminal of said output device in succession to thesegments of the first series in synchronism with the assignment of saidcomposite channel to the single channel and means running synchronouslywith the first-mentioned means for connecting the segments of the secondseries in succession to the coil of said relay.

2. In apparatus for converting to start-stop signals the synchronouscode unit signals received over a single channel from a compositechannel of a time division multiplex system, a series of segmentscontaining one segment for each synchronous code unit signal, a secondseries of segments having one segment for each synchronous code unitsignal and also for a start and a stop signal, a connection between eachsegment of the rst series and a separate one of the segments of thesecond series, a connection between the remaining start and stopsegments to different potentials in the source of supply, a condenserhaving one terminal connected to at least the first and third segmentsof the first series, a second condenser having one terminal connected atleast to the second segment of the first series, a line relay having acoil with one terminal connected to an intermediate potential in thesource of supply, a signal output device connected to said singlechannel having one terminal connected to the remaining terminals of saidcondensers, means for connecting the other terminal of said outputdevice in succession to the segments of the rst series in synchronismwith the assignment of said com-v posite channelA to the single channeland means running synchronously with the rst-mentionedr means forconnecting the segments of the second series in succession to the coilof said relay.

RICHARD E. MATHES,

